"Dry" cleaning compositions for cleaning carpets, rugs or broadloom or the like have been developed and with the improvements of recent years have been shown in use to be particularly effective in removing soil and contaminants therefrom.
"Dry" indicates that the cleaning compositions can be handled in the form of a powder that will flow at room temperature although such compositions may contain a considerable amount of liquid such as water or organic solvents. Such "dry" cleaning compositions have a high soil or contaminant removal capacity so as to extract same over a relatively short interval of time.
"Dry" powdered cleaning compositions of the type to be employed in the improved method and apparatus of this invention may take the form of polyurethane, polystyrene and phenol-formaldehyde resin particles combined with water, an organic liquid, and a surfactant, as set forth in U.S. Pat. No. 2,015,972.
Another "dry" powdered cleaning composition likewise effective in removing soil or contaminants is derived from solid polymeric urea-formaldehyde particles from about 10 to 105 microns in size and a suitable solvent as described in U.S. Pat. No. 4,013,594.
Still another suitable composition is disclosed in U.S. Pat. No. 4,108,800 wherein polyethylene glycol is added to a semi-dry cleaning composition such as that set out in U.S. Pat. No. 4,013,594 to prevent adhering of the very fine particles of the composition to the fibres, which occur in part from the breakdown of the larger particles due to abrasion and thereby increase overall efficiency in the recovery of such residues by a suction- type cleaner.
"Dry" carpet cleaning compositions are expensive. Accordingly the effective and efficient application of same is desirable and may be a critical factor in some circumstances, considering the cost, as to whether such a treatment should be undertaken.
One early example of an applicator for such compositions is illustrated in U.S. Pat. No. 2,632,538 which includes a rotatable foraminous hollow cylinder adapted to be filled with a "dry" powdered cleaning composition which passes therethrough and to be distributed thereby over the surface of the fibrous floor covering when the cylinder is rotated.
Brushes carried by the frame of such unit are used to work the particles of cleaning composition into the fibres.
Other applicators that utilize similar structures are found in U.S. Pat. No. 3,289,240 and U.S. Pat. No. 4,381,156.
A more recent example of applicator, marketed under the trade mark KENMORE, includes a wheeled lower main body portion of an upright suction or vacuum cleaner provided forwardly with a hopper thereabove mounted to extend over the rotating brush or beater thereof.
Such hopper is provided with a pair of spaced apart discharge slots or orifices each having a fixed perimeter or cross-section positioned forwardly and lowermost, through which the dry powdered cleaning composition is adapted to be discharged in spaced apart streams under gravity aided by a selectively driven bladed dispensing roll mounted for rotation within the hopper so as to agitate the particulate material and direct the flow towards the discharge slots or orifices.
According to this arrangement the particles of cleaning composition are deposited somewhat unevenly and are adapted to be spread and worked into the fibres by manipulation of the appliance in which the rotary brush is driven in a direction reversely to the normal forward direction when the appliance is used for vacuuming.
Clogging of the spaced apart discharge orifices from the hopper of the aforementioned unit often occurs requiring the apparatus be shut down and the orifices cleared during the operation.
Subsequently after the elapse of an appropriate interval of time the appliance is converted to operate as a suction or vacuum cleaner with the drive to the brush or beater reversed to rotate in the forward direction to loosen the residues and other debris which are then taken up into the nozzle of the unit and carried to the collection chamber therein for later disposal in the well known manner.
No shut off or effective closure of the discharge orifices is included in the KENMORE unit so that all of the cleaning material is usually dispersed in the operation at hand or must be drawn into the suction recovery passageway where the apparatus is activated to operate as a vacuum cleaner.
Nor does there appear to be sufficient suction generated with such appliance to recover in a satisfactory way the very finely divided residues which when taken up in the dirty air stream tend to escape into the atmosphere through the mesh of the disposable bags or fabrics used to contain same, which fine particles collect on the surfaces of furniture and floor coverings in the surrounding area.